l6 Running Hot

[50bomb]

So took the 67 chevy truck for its first time out legally for a test drive. It has a inline 250/th350. I noticed the water tempature gauge needle on Hot and it felt hot. So I took off the water neck and put a new thermostat in and its still to hot. We replaced the water pump,freeze plugs. Did a whole tuneup on the truck a couple months ago. Not sure what it could be. Thinking maybe I should just ditch the thermostat?

[BOHICA-Chevy68]

don't ditch the thermostat. it's there for a reason. it stops the coolant from circulating until its at the right temp. this lets you engine reach the operating temp in the time it was designed for. if you want to check to see operating, then boil it in some water and you should see it open. you should check your radiator and do a good flush. it may be that your cooling channels could be plugged up reducing the size of your radiator. also check fluid level. if you drained your system for your tune up, it could have pumped the new violent throughout the engine, but not have enough now for the coolant system.

check your heater core and heater system. these systems don't have much to it. so track down the reason why your not getting it cooled. if the coolant system checks out there could be an issue with your water jacket. that's the worst case though. good luck and let us know how it goes.

[pritch]

Yeah-I just went through all this. I did a super-flush job on my block and radiator, removed a wrong, broken fan shroud-basically put everything back to stock and it seems good, now. I'll know more when it gets warm again.
Good luck. It should be easy to figure out

I just thought of something else-you said that you don't have a heater and that your heater hose is just blocked off? I think that the hose should complete it's circuit, that is, from the outlet below the thermostat back to the water pump.

[zeeklu]

I went through all of this myself. It ended up being the gauge. Chris
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[50bomb]

First thank you all for replying. I have a brand new 4 core radiator I bought off a board memeber here. I flushed the inline 250 with a hose before I replaced the freeze plugs. This was several months ago. I just put in a new 180 thermostat and also I do not have a heater so the PO of the inline six that I also bought off a board member here for the same year 67 chevy truck put a bypass hose on water pump inlet/oulet and its pitched. BUT I thought that would not matter being that you can plug those outlet/inlets if your not running a heater? SO again maybe its just the gauge acting silly? It does go back down to cold once I let it sit and cool down. Also again no water is leaking from anywhere. I sure hope its just me over reacting and I dont end up blowing my lil six. I bought this truck back in 2010 and this is the first time we got in road ready or what we think. Really want to make this a daily driver. SOrry for long post.

[PanelDeland]

Take off the radiator cap.Star the truck and let it warm up.Then stick a thermometer in it.Look to see if coolant is flowing thru the radiator.If th thermostat opens coolant will flow.If the thermometer doesn't go above about 180 then your guage may be giving a false read.Or your sending unit.

[50bomb]

Update took my truck on a mile or 2 drive to a buddy's house this morning. The original temp gauge is reading about the half mark. Seems alot better now. I dont know if it has to do with the weather being cooler in the morning or not.

[68gmsee]

A four row is way more than you need for a 250 so if it still runs hotter than you like to see it (normal is 180-195) and you have checked the easy things, install an overflow container for starters.

I have a 250 with a 2 row on mine and it used to run hot, especiall in the summer when it got above 100º. I did the same checks you probably have done like new proper psi cap, lower radiator hose, t-stat, etc.. After I installed an overflow tube, the temp got better. I think, in my case, it wanted a completely full radiator.

forgot: One more thing I did was to install a radiator cap with a temp gauge on it from AutoZone. My internal gauge is close to it but always seems a little higher than the cap gauge by about 3-4 degrees.

[50bomb]

Well I believe it is my original water temp gauge in dash that is not reading right. I took the advice of one of the members here. He said if the needle reads on half-hot and my hand stays on radiator then that means that the gauge is not workin correctly. Sure enough within minutes of running the truck the needle went to hot but engine was very cool. So gonna run a universal temp. Also I did add a 180 thermostat. What should my temp read at? Thank You

[50bomb]

So again I tuned up the inline 250, has a brand new 4 core and 180 thermostat. Temp is reading 220. I was told that is alil over what it should be reading and I was told by others that should be ok and that these inline run hot. Iono Guess I will just run it as is and hope it doesnt over heat.

[50bomb]

Correction: 210 its running at. Went for another 2 mile drive and thats what it wants to stay on.

[Wootdog]

Do you have a radiator shroud on it? What type of fan setup? Driven by a belt? If so, is it tight? Do all the fan blades look the same when it is running? No bent ones? Or electric fans? I think it would run below what you are seeing. Look at the others posts again. You are missing something here.
Kerry

[USSkoval]

My old inline six always ran about 230* in the summer time. It had an aftermarket gauge so I assume it was fairly accurate. The hotter temps never gave me an issue.